Electromagnetically operated typewriter



March 3, 1959 A.VE. AUERBACH 2,375,879

' ELECTROMAGNETICALLI OPERATED TYPEWRITER Filed A ril so, 1956 4 Sheets-Sheet 1 March 3, 1959 A. E. AUERBACH 2,875,379

. ELECTROMAGNETICALLY' OPERATED TYPEWRITER Filed April 30, 1956 4 Sheets-Sheet 2 March 3, 1959 A. E. AUERBACH 2,875,879 I ELECTROMAGNETICALLY OPERATED TYPEWRITER 4 Sheets-Sheet 3 Filed April 30. 1956 J62 INVENTOR.

3, 1959 A. E. AUERBACH I 2,875,879

ELECTROMAGNETICALLY OPERATED TYPEWRITER Filed April 30, 1956 4 Sheets-Sheet INVENTOR.

5%M W r ables, are divided generally into three classes.

typewriters are subject to several drawbacks.

I 2,875,879 I Piitented Mar- 1 959 United vStates Patent ELECTROMAGNETICALLY OPERATED TYPEWRITER Application April 30, 1956, Serial No. 581,421 16 Claims. (Cl. 197-14) This invention is concerned generally with a typewriter, and more specifically with an electromagnetically operated typewriter.

:So-called oifice typewriters, as distinguished from port- These comprise the conventional typewriter, the noiseless typewriter, and the electric typewriter. The conventional oifice typewriter'ofters the advantages of lowest cost, and relatively lightweight. Such machines also can be' used where no electricity is available, but this is a negligible consideration in modern oflices. 1 However, conventional Considerable physical efiort is necessary on the part of the typist to operate the machine. The type bars are thrown against the ribbon and paper, and this causes considerable noise. Furthermore, there are considerable physical shockspresent. These features cause the machine to get out of adjustment, and to wear out relatively rapidly. Furthermore, they fatigue the typist unduly.

The noiseless machines are provided with a lever action such that the type bar is thrown near the ribbon, and the mechanism then operates the type bar to move the type face against the ribbon with somewhat of a pressing motion. This reduces noise substantially, but does not completely eliminate it. This type of machine is somewhat heavier than theconventional machine, and it ismore expensive. Somewhat more effort may be required on-the part of the typist, and although the shocks are lessened, thereby decreasing wear on the mechanism, the mechanism is more complicated, and repairs or adjustments are likely to be more expensive. 7

Electric typewriters require :little physical efiort for operation, can type at a slightly higher speed, produce uniform typing impressions, and can make a large number of uniform carbon copies. However, maintenance of electric typewriters is likely to be relatively expensive, and the initial cost is substantially higher than conventional or noiseless machines. There is no touch to an electric typewriter, since the slightest depression of a key causes a typing operation to be completed automatically. This is undesirable to many typists. The continuously running motor of present electric typewriters often is noisy, or may become noisy with age, and may be left running accidentally for long periods, thereby wasting power. Furthermore, should two keys be depressed simultaneously through inadvertence, the corresponding type bars are likely to. be thrown into violent collision and thereby damaged. Electric typewriters also are considerably heavier than the conventional and noiseless machines. H 1

It is the general objectof this invention to produce a typewriter eliminating substantially all the disadvantages of previous machines as set forth above.

More specifically, it is 'an object of this invention to provide a typewriter operable with adegree of silence never before achieved, and specifically wherein the type face is pressed against the ribbon in the printing operation. i

, typewriter of relatively Another object of this invention is to provide a type.- writer requiring substantially no more physical effort than the present electric typewriter, but retaining the touch of conventional machines.

It is an object of this invention to provide a simplified lightweight construction, thereby facilitating portability, reducing the cost of manufacture, and reducing wear and maintenance.

More specifically, it is an object of this invention to provide a typewriter wherein all printing stresses are confined to the type heads, thereby reducing shock and vibration and contributing to ease of typing and to iongevity of the machine.

A further object of this invention is to provide an electromagnetically operated typewriter wherein a single electromagnetic device operates on all type bars.

It is a further object of this invention to provide an electromagnetic typewriter wherein all circuits are keyed by the type bars themselves, thereby eliminating problems of synchronization and linkage adjustment.

It is a further object of this invention to provide a typewriter wherein adjustment can be made to produce uniform carbon copies regardless of the number of such copies, within wide limits.

Still another object of this invention is to provide a typewriter having a single electromagnetic device for making typing impressions, for controllingthe carriage release, and for returning the carriage.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein; v

Fig. 1 is a side view, partially in section, of certain of the operating parts of a typewriter constructed in accordance with the principles of my invention; 7

Fig. 2 is a view similar to Fig. 1 showing the parts in a diflerent position of operation; V Fig. 3 is a top view of the operating parts shown in Figs. 1 and 2; 7 I

Fig. 4 is an electrical wiring diagram illustrating the electromagnetic parts of the invention; r Fig. 5 is a side view on an enlarged scale of a portion of the type head; 7

Fig. 6 is a side view generally similar to Figs. 1 and 3 and showing a modified form of the invention; I

Fig. 7 is a vertical sectional view as taken along the line 7-7 in Fig. 6;

Fig. 8 is a horizontal sectional view taken alongthe line 8-8 in Fig. 6;

Fig. 9 is a vertical sectional view taken along the line 9-9 in Fig. 6; V

Fig. 10 is a side view similar to Fig. 1 and showing a modified form of apparatus;

Fig. 11 is an enlarged side view similar to Fig. 5 and showing a further modification; V

Fig. 12 is similar to Figs. 5 further modification;

Fig. 13 is an electrical wiring diagram used in connection with the device of Fig. 10;

. Fig. 14 is a view similar to a an adaptation of the apparatus advancing mechanism;

' Fig. 15 is a view of the electromagnetic mechanism as modified to effect return of the carriag v v Fig. 16 is a view partially in section taken along the line 1616 of Fig. 15; z Fig. 17 is a side view of the modification of the invention as shon in Fig. 6 adapted for carriage return;

Fig. 18 is a view of the mechanism in Fig. 17taken substantially along the line 18-18 in Fig. 17; and Fig. 19 is an enlarged fragmentary view of a'portion' of Fig. 17 showing the parts in greater detail.

and 11 and illustrates a part of Fig. 4 and showing for operating the carriage re lient strip o en a m n with Referring now in greater particularity to the drawings, and first to Figs. -14, there will be seen the usual typewriter platen 30 having a sheet of paper 32 in typing position ereon. The typing ribbon 34 is in its accustomed po s itio" ifi' frontof thesheet of paper'32 and opposite ;to platen so. Aseries of t pe bars 36 anyone being shown) of more or less conventional construction is lpivotally mountedat 38. Reference hereinafter will be'rnadeto the singleillustrat'ive type bar an accompanying Z' and it he"understood that all parts are inulti plie'd, where necessary, in accordance with the necessary number of type bars. 1 More specifically, the type bar ;36 na a' pe head or pallet 40 having a type face 42 thereon adapted to' engage the ribhoni34 for forming a typing impression bathe paper 32. The type bar is provided a'sllig 44 of magnetically susceptible material such as softiromand this slug is mounted irnn-iedi'ately below -the ty e-paid,ar'pquetb means such "as the dovetail 46 illustrated. In additionft he slug would be welded or soldered in place 'once' it was determined which size or weight'sln'g wasitobe used with any'givenftype face. A single stop or rest 48 is provided tor all of the typebars te 'hold their] irlidle position as shown in Fig. 1. I

for each type bar 36 there is provided a ;key lever 50 pivoted M52 and having'an upturned outer end carrying a y'54 of knownconstruc'tion'. A'stop or rest 56 is I pfo'vided beneath the inner end of all of' the -key levers,

and a spring 58 is provided for each key tending to hold the associated fkey"leveragainst'this stop. Onthe inner endof each keylever 50there is pivoted a dog or jack 60 at "62, and thisd'og orjack' is urged by a spring 64 against a stop 66 for bearing upwardly beneath a projecting shouldei' 67 on the type'b'ari" i Depr'ess'ion of a key 54 and accompanying pivotal mavem'sfitar the keyleve'r'50 willcause the type bar 36 to be moved upwardly from the position shown in Pig: '1 through the dashedline position ofFig. 2 to the solid line position of Fig. 2 in contact with, or substantially in contact wi 'th," the' ribbon 34? As the t'pebarssap proaehes this limited position, the jack of dog '60 pivots against the force of the spring 64 and slides oif of the shonlder'67 as is shown in full lines in Fig. 2, thus freeing the type bar for partial return, as to the position shown in dashed'lines'in -F-igQ2. However, the force with which the type bar'is moved into proximity with the ribbon 34 is by design not 'sufiicient to make a typing impress'ion, and additional means are employed for this purpose as now will be described;

An upwardly'directed, generally C-shaped electromagnet 68 is"pos i'tioned below and in front of the platen 30. The electromagnet is provided with a'pair of'pole pieces winprsxim'it to the ribbon 34, and 'positioned'so that the magnetic slug 44 of any type bar willpa'ss between the sales. The poles are beveled as at 72, or otherwise are provided with guides to insure centralization of the -slfig and hencc of the t pe head Oi pallet 40 in the event that ,a type bar should be bent in use. The electroi'nagnet68 'further inclildes an energizing coil 74 con nected in a manner shortly to be destined? i K'nonniagnetic strut 76 extends across the front of the elec tromagne t 68 the central portionofthe strnt being displaced' into the plane of theelectromagnet, and a resilient strip or leaf spring 78 is mounted on this strut with ts il iir 9 s Prot n t wa d h ac et h polesvo. 'A roller 80 is carried at 'thelupper end of the the rnagnetie" .slug 44,although"it readily could be made engageable'with any partofthejype bar 36. An insulated switch actuator 82 is carried by the resilient strip 78 on the backside thereof, switch contacts 34 carried by resilient arms 86 sup t ti i mthe st 6 r g sdr n c' .1-

, cut as shown iniEig. 2 when theresilient strip '78 1s deflect defenegmearor the slug 4 against the r9ug V L Theelectricalcircuit as shown'inFig 51 includes a in];

wave bridge rectifier 88 connected to a flexible cord or wire 90 having a=plug (not shown) thereon tor-insertion in the usual electrical outlet. The positive side of the rectifier is connected to a junction point 92, while the negative side is connected to a bus 94. The bus 94 is connected to one end of the coil winding 74, and the other end of the coil winding ,is connected to the fixed contact 96 of a relay 98. The relay includes a coil 190 and core 102, toward which an ar-mature 1114 is attracted against the force of a spring 106. The armature is connected to a a and s b i sqnnsq d thtqvsh a es sto 0 of high value to the wj lincltior po ir1 t. 9 2.

"One end of the relay coil is connected directly to the bus 94, while the other end is connected through a wire 112 to one of the contacts 84. l heother contact 84 is connected through a wire 114 to the junction point 92.

A capacitor 116 is connected between the wire 108 and the bus 94. Additional capacitors 118 are arranged to be switched .i' to parallel with the capacitor 1-16 ;-by means of switches 120. A

The capacitor 116 normally is charged from the rectifier 88 through thehigh resistance -When -a-key is depressed, and the type ;bar 36-is thrown'toward the'full line position of Fig. 2, in .the manner previously described, the switch contacts ;84 are brought into engagement. This causes energization of the relay :98, and causes the armature 1041c close against the --fixed contact .96. This causes the capacitor Ell- 6, and any of the capacitors 118 that mightbe' switched into-the circuit, to be discharged substantially instantaneously through-the electromagnet coil '74. This causes the poles 70 to .exert a sudden and powerful attractive force on the slug 44, and thereby to press the type face 42 against the ribbon 34 to-form a typing impression 'on' the paperBZ. Since this magnetic force is not applied until such time as the type face is in engagement with the ribbon, or very nearly so, the typeface acts to form the typing inip'ression Withapressingforee. i

"It will be appreciated that the .resilient strip or -leaf spring 78 is tensioncd -by engagement of -theroller -80 by the slug 44. The condenser or capacitor 116 discharges substantially instantaneously, and cannot recharge instantaneously due to the resistor -1-1-0. Accordingly, immediatelyupon formation of the "typing imprfession, the spring or strip 78 straightens out by {virtue of its resiliency, and starts the type bar aback past the dashed line positionof Fig. 2 tow'ard its initial'position as shown in' Fig. *1. Release of the key 54 allows the key lever 50 to return its initial position under the influence of spring 58, and thejack or dog 60 thereby snaps 'underth'e shoulder 67. '-It wi-ll-be appreciated that the s'ize'of the 'resisto'rf11-0 is chosenso that the capacitor 1'16'readily will'lr'echarge in 'the time between strokes of" a 't'ypists' fingers, but will not recharge sufiiciently rapidly tspreclude' return of a key bar 36 :towan d -it s initial position under' the influence of the leaf spring dr'r'esnieiit strip 7 8. A 4 I i V "rm/111 beapparent that greater force is needed .to make typing impressions of a predetermined quality with some characters than-is necessary with other characters. For example, the very'small area of the period type face does not req' ire nearly {the force for making an impression that the large area of other characters, for in stance the letter whiteness; a Thus-means is provided for varying strength oif the ma'grietiepressing action in accordance f'gre required. Mo re specifically, with reference to'FigTS, there will be seen a type b r 169 h i th t e hea P l e 5nd tripe ta 524- E h 'pdse 9f i lu a i i b p su'rned that'the character lof u 4' a ar e are than I The m e cal 1 is was 9 e i 4. S g l-t lis s l l an?? Pi? .s i was bait, and the type face'42a is pressed against the ribbon wijh greater force than is the type face 42, whereby a uniform impression is obtained. By this means, a degree of control is exerted over the impression forming force without requiring extensive differences among the type bars and type heads or pallets. It will be understood that the dovetails form a force fit, or that other means are provided to lock the magnetic slugs inplace. so that they will not be displaced laterally from the type bar by engagement with the tapered guiding surfaces 72 of the magnet poles 70 in the event that a type bar should be bent.

A modification of the invention is shown in Figs. 6-9. In this form of the invention, only a single magnetic pole is used, and by this means the magnetic force can be made to centralize the type head or pallet. Many of the parts are similar to those previously shown and described, and similar numerals are utilized with the addition of the suflix b. Thus, the type bar 36b remains substantially the same as previously described, including the type head or pallet 40b, the type face 42b, and the magnetic slug 44b which may be held in place by the dovetail 46b. An abutment shoulder 122 is provided on the type bar substantially at the junction with the type pallet, and immediately below the magnetic slug 44b.

The electromagnet 68b in this case comprises a magnetizable core 124 mounted on a fixed part of the machine, and including the coil winding 74b. The core has only a single pole 70b, and as will be observed particularly in Fig. 7, this pole tapers to a narrow face 126. of substantially the same width as the slug 44b, it being understood that this slug is of the same width as the type pallet or head. Accordingly, when the pole tip 126 is magnetized, it centralizes the slug 44b, and hence centralizes the type face 42b.

The flexible switch blades 86b carrying the switch contacts 84b are mounted behind the magnetizable core 124, and may be supported therefrom by means such as a nonmagnetic support 127. Alternatively, the switch blades can be supported from any fixed part of the machine.

The magnetizable core is provided opposite the abutment shoulder 122 with at least one pair of lugs or ears 128. These lugs or cars fit within the channel sides 130 of a square switch actuator 132 surrounding the core. The switch actuator rides on the lugs or ears 128, and is provided with front and rear cross pieces 134 and 136 respectively. Coil springs 138 are compressed between the lugs or ears 128 and the front cross member 134 to urge the square actuator forwardly, such movement being limited by abutment of the rear cross member 136 against a nonmagnetic stop 140 on the back of the magnet core 124. The front cross member 134 is positioned for engagement by the shoulder 122, and a switch engaging insulated member 82b is mounted on the rear cross member 136 for engagement with the forward one of the switch blades 86b.

Accordingly, when the type bar 36 is pivoted in the same manner as heretofore disclosed, the shoulder 122 engages the square actuating member 132 and presses it backwardly against the force of the springs 138, thereby causing the switch engaging member 82b to deflect the switch blades 86b, thereby effecting contactingof the switch contacts 84b. This causesthe circuit through the relay coil 100b to be closed in the manner previously described. As set forth heretofore, this causes energization of the relay coil 74b, and the magnetism of the pole 70b attracts the type bar and type head or pallet through the magnetic slug' 44b, whereby to form'a typing impression. Immediately upon discharge of the capacitor or condenser the springs 138 start the type bar back toward its rest position. 1 v

' In accordance with the embodiments of the invention heretofore shown and described, a spring element is stressed by the type bar, and imparts movement to the type-bar to return it toward its normal position. In Figs.

. 6 a l0 and 13 there is shown a system wherein a positive return impulse is applied electromagnetically, In this. form of the invention; most of the physical parts remain as previously described. Thus, there is a type bar 360 having a type head or pallet 400 with a, type face 420 thereon, and carrying a magnetic slug 44c.

The slug 44c engages the upper end of a lever 142 pivoted at 144 on a fixed part of the machine, and carrying one of the switch contacts 840. Pivoting of the lever moves this switch contact 84c into engagement with the other switch contact 840, thereby completing the circuit in the manner previously described. The lower end of the lever 142 is pivotally connected at 146 to the plunger 148 of a solenoid 150. V

The wiring diagram ofFig. 13, accompanying Fig. 10, is similar to that shown in Fig. 4, and operation thereof will be obvious. In connection with this diagram, it will be seen that the capacitor 1160 is charged through the resistor 110a and the armature 1040 is pulled down against the contact 96c by energization of the coil 1000' upon discharging of the capacitor by closing the contacts 84c. This causes instantaneousenergization of the coil 74c, whereby a typing impression is formed. The solenoid 150 is connected in parallel with the coil 74c through a delay circuit 152 of any known or suitable design. Therefore, very shortly after the formation of the typing impression, the solenoid 150 is energized. This causes pivoting of the lever 142, and the typebar 36c is positively started back toward its initial position.

Reference previously has been made to varying the size of the slug, as 44, 44a, in. order to vary the force for forming a typing impression. In some instances it might not be desirableto change the external size of the slug, and in such instances a slug may be used as shown in Fig. 11. In Fig. 11, the parts are similar to those previously shown and described, and include a type bar 36d having a type head or pallet 40d with a type face 42d thereon. The difference resides in the magnetic slug 44d, held in place by the dovetail 46d, in that the slug is provided with bores 154. The size of the bores, and also. the number thereof, may vary from one slug to another, thereby varying the volume of the slug, and hence the magnetic force exerted thereon.

The slug also may be varied as shown in Fig. 12, wherein the parts just enumerated again are shown, this time with the addition of the sufiix e to the identifying numeral. The distinguishing feature in this instance is that the front of the slug Me is toothed or corrugated as at 156 in order to reduce the volume of the slug. It will be understood that in some instances it might be desirable to vary the external size of the slug, while boring of the slug, or toothing or otherwise externally shaping the slug might be desirable, and that all of these features might be used at the same time o-n'diiferent ones of the type bars of a typewriter constructed in accordance with the principles of this invention. 7

In accordance with all of the foregoing, various means are provided for electromagnetically producing a typing impression. Means is shown in Fig. 14 for also producing carriage advance without the addition of any substantial amount of structure. More particularly, Fig. 14 again shows the electromagnetic structure 68 similar to that previously described, having the poles 70]", the strut 76f mounting the leaf spring or resilient strip 78 having the roller at the upper end thereof, and the energizing coil 74 wound on the electromagnet. The distinguishing feature in this instance is that the core of the electromagnet has a recess 158 for-med in one side thereof. A

bell crank 160 is pivoted near the electromagnet 68f at 162 and is provided with a magnetically susceptible slug 164 capable of movement into the recess 158. The opposite end of the bell crank is pivotally connected at 166 to a link 168 which is connected to the carriage advance mechanism in place of the usual universal bar. It will be understood by those skilled in the. art that the universal i m-51m ns i n hs rsal b "S mp. L y of the electron;agnht, th 1,64 lsjitt l' l titfi .rnto the recess 158, thereby effecting a pull on the link 16.8, and .qperationof the carriage .advance. It .will he appreeiated that provision must 'be madelfqrcarriage advance by the spacer bar, and accordingly the space r.is provided with aswitch 170,( Fig. 4.) in-parallelwiththe switch contacts .84. Thus, whenever thespacenbarisaetuatedto close theswitch contacts 170,

V i V Z l d, an d the capacitor 116 will h sh shs ss to l- 1 9341 s s m ns 68, th e pivoting the bell crank 160, and operating the carriage advance.

' In, accordance with a preferred form of this invention, me also is g a d! (t sl st cm n s l returning the carriage. finch rneans is-shown in Figs. and 16. In in pire th ale-F r man tru ur s h s be modified somewhat, .havinga pair of straight side arm core portions 172 carrying the poles 70g. The sidearm portions .are, connectediby a tubular magnetic section 174, and a magnetic core of plunger 176 is mounted within the hollow portion;17;4 A tubular end cap 178 carries a compression spring 180 .which urges the plunger 176 to she right. However, the plunger is normally held nside the hollow portion 17, gtby acatehordetent 182. The catch or detent comprises a plunger retractable into a solenoid .1851 against the force of .a biasing spring (not shown) when the solenoid is energized by closing of switch contacts 186. These switchcontacts are closed by a special key or the like provided on the typewriter in a e o th u u l g n iass sth n s sr- Al e na e y. this mechanism can be utilized in addition to the usual manual carriage return.

On the vouter end of the plunger 176 there is provided 518! Yislds l in a l i e d e io (Fi .16) against the force gt a spring 190. When the plunger is moved outwardly under ,theinfluence of the spring 180, the hook 188 snaps ,over one arm 192 ,of a lever 194 piyqted ,at 19.6 .on ,a fixed .part 198 ,of the machine. The opposite arm 20.0 of the lever is provided with a retractable tip 202 .urged outwardly ,by a spring 204, and this retractable tip is .engageable' with rack teeth 206 which may be formed directly On .the carriage, or which may be connected through suitable linkage, including the possibility of .a fleidble cable, or other suitable means. In dditi n t th sh prh o th k 88 ver the lever arm 192, the outer lend'tof the plunger 176 engages one of a pair of flexible switch blades 207 to force contacts 208 carried thereby into engagement. The switch contacts, as may be seen in Fig .4, are connected in parallel with contacts .85 and the contacts 170, whereby to energize the coil 74g of the electromagnet srtuduIc 68g.

Wh h this car es? ha ash m d as f s s d r ble and the typist desires to return the carriage, all that is hs ssa i to what t e but n o lever to Close the wit h c n est 156- Ihi s ns s et a n o h de 1 8 2, and the plunger- 1716 is released. This causes the plunger to be "expelled by the spring 180, and the hook 188 engages the Tarrn of the lever 194 as aforesaid, the w t h on a t 20. si u t neousl b g s This effects discharge of the capacitor 116 through the relay coil 74g, and the plunger 176 is snapped back to its initial qsiti n- Th se es piv s of the lever 194, d causes the carriage to be started rapidly toward its return position. The spring loaded arm 202 of the lever allow's' the tip of the lever to move along a linear path, and to remain in engagement with the rack teeth 206 I The throw will not be enough, in most :cases, to move the carriage completely to its returned position, but such returning will be accomplished :by inertia of the carriage. In this connecfion, it will be appreciated by those skilled in the art that a typist does not keep her hand on the manual re.- turn lever untibthe carriage is completely returned, but

:8 othe im art a sna ac o th yardag that causes it t s' f l stamsdr siti n t vi ue-of th inertia tha im a sd i A bd fiqati 9 h inv s at retur in h sa riage when used with a single pole magnet such ,as ,in Fig.. 6,is shownin Figs. 17-19. The parts in this instance are equivalent to those justdescribed'withregardtofigs. 15 and .16, in most instances, andsimilar numerals are used with the addition of the suflixh. Extendeddescription therefore ,is believed unnecessary. Most particularly, the magnet core 12411 is provided with a 'relativelynrovable plunger section 176h which is normally pulled outwardly by a spring 18%. This normal outward pull is resisted by a detent 18211 ,OPera-ted in the manner described above. When the detent 182]; retracted, the plunger portion 176h of the core .fiies outwardly under the influence of a spring to close the swi ch .QQntacts 208k, the hook 188k engaging the arm 191211 .of the lever 194k. Closing of the switch contacts 208k causes energization of the coil .7411 in the manner aforesaid, and .this causes the plunger portion 176k to be .drawn back toward the fixed core part 12%, the lever 1941;

thereby being pivoted to cause the carriage to be re-.

turned.

It will be observed that in this form of the invention, in .order to provide for operation of the switch contacts 84h and to provide for return of the type bar toward its initial position, a small lever 209 is mounted on the front of the magnet core 124th by means of a pivot 2 110. The upper end of this lever is magnetic, andthe lower end is non-magnetic. The upper end of this lever is struck by the shoulder 12 2}1 on the type bar as will be apparent particularly in Figs, 17 and 19, and this ,eliects' pivotal movement of the lever 209 suificiently to cause the tail thereof to engage the switch contacts 84]; carried by the flexible arms 86h, whereby the switch contacts 84h are closed, and the core 12411, 17611 is magnetized by the coil 74th. This causes a typing impression by attraction on the magnetic slug 44h, and further causes additional pivoting of the lever 209, the upper end thereof being attracted by the upper end of the core 12.4h, to load a spring 212 stretched between the core and the tail of the lever. As soon as the capacitor has been discharged through the coil 74h, the magnetizing force of the core 124/1 dissipates, and the spring 212 pivots the lever 209 back toward its initial position, thereby starting the type bar 36h back toward its rest position.

In order to preclude noise in operation, a nylon or other satisfactory washer 214 is interposed between the coil 74/1 and a stop 21.6 on the core portion 176/1. Similarly, nylon pads are placed on the core 12% at 21.8, and on the tip of the lever 209 at 220.

As will be understood, all parts within magnetic range of the clectrornagnet, and not specified or implied as be mg magnetic or magnetically susceptible, are .made .of non-magnetic materials.

From the foregoing it will be apparent that many ad vantages are possessed by the novel electromagnetictype? writer herein" disclosed. The efiort required for the op eration of this novel typewriter will be on a par with that required by present electric typewriters, but it will retain the virtues of the touch of a conventional type.- writer. This typewriter will be exceedingly quiet in operation due to the pressing nature of the type impression forming operation as compared with the usual slapping motion. There is no continuously running motor, which, if not noisy at first, will tend to become noisy with wear. The machine will be less costly to manufacture than pr s nt elec ri yp e d e t t s m lic y, the s imu on of an e tr mo o and due to the edu d effort of assembly brought about by the fewer parts; S e th ho k an ib a ion i he in o ent on m ua and elect m chine i re y r du d, the 9- tire chassis of the typewriter may be of lighter and less expensive .design. Similarly, the type bars-can be less rigid. This reduction of shock and vibration furthermore will lead to longevity of the typewriter and to substantially lowered repair bills, and to lack of fatigue of the typist.

The character of this machine is such that all printing stresses are confined to the type heads. This is partially responsible for the reduction of shock and vibration as noted heretofore. Damage to type bars through inadvertent striking 'of two or more keys simultaneously is unlikely since very little force is applied to the type bars until they reach the electromagnet, and the magnet can supply power to only one type bar at a time.

High speed of operation is possible since little manual eifort is required, the throw of the type bars may be quite short (since the energy for printing is not stored in the inertia of the type bar) and a shorter throw means less. travel time, and the lighter weight construction of the entire type bar linkage, from key to type face, leads to less inertia, and consequently faster operation. Due to the constant power of the electromagnet, the typing impressions willbe uniform, whereas many typists find it difiicult to form uniform impressions 'with the usual manual machine. Furthermore, by expedients such as changing the number of capacitors in the circuit, the power of the electromagnet can be adjusted to compensate for the number ofcarbon copies to be made.

An important structural feature is that the switch for the electromagnet is operated by any type bar during a typing operation. Accordingly, no problems of synchronization or linkage adjustment are presented. The use of the single electromagnet for forming typing impressions, and also for effecting carriageescapement, and for effecting carriage return is of considerable importance.

It is to be understood that the illustrative embodiments of the invention as herein shown and described are capable of variation without departure from the spirit of the invention. Accordingly, it isto be understood that all variations such as fall within the spirit and scope of the appended claims form a part of this invention.

The invention is claimed as follows:

1. In a typewriter having an impression-forming area, a movably mounted type bar having a type face thereon, and a key for moving said type bar to a position adjacent said impression-forming area, the combination comprising an electromagnet operable on said type bar when said electromagnet is energized and having an iron core positioned beyond the path of movement of said type bar for attracting said type bar to urge the type face thereof toward said impression-forming area to form a typing impression, a switch closed by said type bar as it approaches said impression-forming. area, and electrical circuit means interconnecting said switch with said electromagnet upon closing of said switch to energize said electromagnet.

2. In a typewriter having an impression-forming area, a movably monntedtypebar having atype face thereon, and a key for movingsaid type bar to a position adjacent said impression-forming area, the combination comprising an electromagnet having a generally U-shaped iron core with a pair of confronting poles positioned for said type bar to pass between said poles, said electromagnet being operable upon energization thereof to act on said type bar to urge the type face thereof toward said impression-forming area to form a typing impression, switch means closed upon operation of said key and type bar as a type bar is positioned adjacent said impression-forming area, and electrical circuit means interconnecting said switch means with said electromagnet to energize said electromagnet upon closing of said switch means.

3. In a typewriter having an impression-forming area, a movably mounted type bar having a typeface thereon, and a key for moving said type bar to a position adjacent said impression-forming area, the combination comprising an electromagnet having an iron core with a pole with which said type bar is brought into alignment and toward which said type bar moves, said electromagnet being operable upon energization of said electromagnet to attract said type bar toward said pole and to urge the type face of the type bar toward said impression-forming area to form a typing impression, a switch closed upon operation of said key and type bar to energize said electromagnet as said type bar is positioned adjacent said electromagnet, and electrical circuit means interconnecting said switch with said electromagnet to energize said electromagnet upon closing of said switch.

4. In a typewriter having a platen, a pivotally mounted type bar having a type face thereon, and a key for pivoting said type bar toward said platen, the combination com prising an electromagnet operable on said type bar upon energization of 'said electromagnet to urge the type face thereof toward said platen to form a typing impression, a capacitor, electrical circuit means for charging said capacitor, switch means closed upon movement of said type bar toward said platen, and electrical circuit means operable upon closing of said switch means to discharge said capacitor through said electromagnet, therebyimpulsively energizing said electromagnet.

5. In a typewriter as set forth in claim 4, the combina'- tion further comprising a plurality of capacitors, and means for selectively connecting all capacitors beyond said first capacitor into circuit with the first capacitor for varying the strength of the impulse applied to the type bar. -6. In a typewriter having a platen, a plurality of pivotally mounted type bars having a'type face thereon, anda plurality of keys for individually pivoting said type bars toward said platen, the combination comprising an electromagnet for individually acting on said type bars as they are pivoted toward said platen, said electromagnet being operable when energized to urge an adjacent type face toward said platen to form a typing impression, a capacitor, electrical circuit means for charging said capacitor, a common switch engageable by any of said type bars upon pivoting thereof toward said platen, and electrical circuit means interconnected with said switch and operable upon closing thereof to effect discharging of said capacitor through said electromagnet, thereby impulsively to energize said electromagnet.

7. In a typewriter having a platen, a plurality of pivotally mounted type bars each having a type face thereon, and a plurality of keys for individually pivot ing said type bars toward said platen, the combination comprising an electromagnet operable on any of said type bars when pivoted toward said platen, means for varying the electromagnetic effect of said electromagnet on said type bars in accordance with the character of said type face to produce a uniform typing impression from one type face to another, said electromagnet being effective when energized to urge an adjacent type face toward said platen to form a typing impression, switch means operable upon approach of a type bar towards said platen, and electrical circuit means interconnecting said switch means with said electromagnet for energizing said electromagnet upon operation, of said-switch means.

8. In a typewriter having a platen, a carriage advance mechanism, a plurality of pivotally mounted type bars each having a type face thereon, and a plurality of keys for individually actuating said type bars toward said platen, the combination comprising an electromagnet individually operable on one of said type bars pivoted toward said platen by its key, said electromagnet when energized acting on a type bar so pivoted to urge the type face thereof toward said platen to form a typing impression, switch means closed by operation of any key and type bar, electrical circuit means interconnecting said switch means with said electromagnet for energizing said electromagnet upon closing of said switch means, and means attracted toward said electromagnet upon energization thereof for operating said carriage advance mechanism.

2. ,In a typewriter ,having a platen, a carriage carrying saidnlaten, .-a P .1 I& i YLQ ,pivotal y m u yn bars a h having a tyn fa e th on, and a pl y of k y for ,ind'vidually pivoting said type bars toward said platen, the combination comprising an electromagnet lectromagnetically operable on any one of said type bars pivoted toward said platen, said electromagnet when energized .being effective to urge the type bar telectromagnetically operated on toward said platen to cause the typeface thereof to form a typing impression, switch rn'eansclosed by movementof any key and type bar, lecjtricalcircuit means interconnecting said switch means with said electromagnet for energizing said electromagnet upon closing of said switchmeans, a part atttacted ,toward :said electromagnet upon energization thereof for eifecting return of saidcarriage, means normally. ho1ding ,said ,part against movement in response to such attraction, .a carriage-return .key, and means oparatively interconnecting said carriage-return key and said holding means for selectively releasing said holding means to free said part for movement thereof by attraction .toward said core whereby to eifect return of aid carriage.

.10. In a typewriter as set forth in claim 9, the combination wherein :the electromagnet comprises a core, andwherein :the part attractable :to effect return of the carriage comprises a movable part of said core.

1- 1. In va typewriter having a carriage and a platen carried thereby, a plurality of pivotally mounted type bars each having a-type face thereon, and a plurality of keys .for individually pivoting said type bars toward said platen, the combination comprising an electromagnet ,haying 'a core, said electromagnet being operable one zata time-on any :type bar pivoted toward said; platen, said electromagnet when energized being eifective to urge-thettype face of such type bar towardsaid platen to a typing impression, switch means operated upon movement of; any key and corresponding type bar, electrical foirouit means interconnecting said switch means with paid electromagnet to energize said electromagnet upon closing of said switch means, ,a movable core part operable upon energization of said electromagnet to fieot 11cm"! of ,said carriage, means normally holding partwagainstmovement in response to such attraca ;c arr;i a-ge: return key, means operatively interoQnneqting,-;-said carriage-return key and said holding means for selectively releasing said holding means to snid part for movement thereof by attraction toward said-gore rwhereby to elfect return :to said carriage, and a pgugt attracted toward .said core .upon energization of rcleotrornagnet to effect advance of said carriage.

, lz -lnla typewriter as set forth in claim 11, the combingtion furthercomprising capacitor means vconnected eircnit by said-switch means for impulsively energizi gv ssaid electromagnet.

13 rhhattypewriter'having a platen, amovably mounted type bar having a type face thereon, and a key for moving said type jbar :toward said platen, the combination comprising an ,electromagnet operable on said type bar-upon energization ofisaid electromagnet to ,urge the type face thereof toward sa'idplaten to form ,a typing impression, a capacitor, electrical circuit means for charging said capacitor, switch means closed upon movement of said type bar toward said platen, and electrical circuit means operable upon closing of said switch means to discharge said capacitor through said electromagnet, thereby impulsively energizing said electromagnet.

l4. Ina typing machine having an impression-forming area, a movably mounted type member having a type face thereon, a magnetically susceptible part on said member and a key for moving said type member -into position adjacent said impression-forming area, switch means closed ,upon such movement, electrical circuit means energized .by such .closing, .and ,an ,electromagnet connected .in said circuit .and energized upon energization of the circuit, said electromagnet having an .iron core with ,pole means complementary to and accommodating said magneticallysusceptible partof said memberto urge .said type face toward said impression-forming area to form a typing impression.

15. In atypewriterhavinga platen,-a plurality,of pivotally mountedtype bars ,each having .a type face thereon, and a .pluralitylzof ;keys for individually pivoting said type bars toward said platen, the combination comprising an electromagnet operable ,on said type bars one .at a time whensaidclectromagnetlis.energizedto urge the type face of the type bar acted .upon toward said vplaten to form atyping impression, a single switch closed by any of said type bars .as it approaches said platen within range of said relectromagnet, electrical circuit means interconnecting said switch with said electromagnet upon closing of said ,switch -to energize said electromagnet, means for terminating ,energization -=of said electromagnet to, release a :tyPe bar for return to initial position,

and electromagnetic means for starting movement of a typebar back toward its-initial position.

16. In a typing machine having an impression-forming area, a movably mounted type member having a type face thereon, ,and a key for moving said type memher into position adjacent said impression-forming ,area, the combination comprising 13.11 electromagnet operable on said type 'member upon energization of said electromagnet to urge the type :face ithereof toward said impression-forming area to form a type impression, a capacitor, electrical circuitzmeans for vcharging said capacitor, switch means closed ;upon -movement of said type member into position adjacent said impression-forming area, and electrical circuitflmeans operable upon closing of said switch means sto discharge :said capacitor through said ,electromagnet, thereby impulsively energizing 'said electromagnet.

Vogel Nov. 25, I913 Talley Jan. '12, 1943 

